Colors are wonderful to look at, but they also affect people in ways besides sight.
They have a powerful effect on how people feel and behave.
Artists know this and so do businesspeople who want to influence how people feel about their products and advertisements.
For example, research has shown that people can be more productive if they are working in a blue room.
The color purple is often linked to wealth and royalty and is seen as a mysterious, spiritual color.
Some colors have even been associated with changes in blood pressure.
Though color can influence how we feel and act, these effects may depend on personal and cultural factors.
Therefore, it's important not to believe everything you hear about the effects of color.
（Different colors can be combined to form other colors.）
Though there are differences between cultures, there is a general agreement about some colors.
The color red, for example, is a warm color associated with energy and excitement in many cultures.
In China red is associated with fire, energy and good fortune.
On the other hand, one experiment showed that exposing students to red before taking a test can have a negative effect.
In fact, of all the colors, research shows that red has the most powerful effect on human behavior.
Certainly, it's interesting and important to better understand the psychological effects of light and color.
To gain a better understanding of these effects, more research is needed.
(Mixing three primary colors creates a tertiary color such as brown or gray.)
